Thanks tons for the tests Ryan! Well, at least the hung task timeout trace is different, so we're making some progress.
With the new kernel it seems that we're stuck in bch_bucket_alloc(). I've identified other upstream fixes that could help to prevent this problem.
If you're willing to do few more tests, here's a new test kernel (based on 4.15.0-54-generic + set of bcache upstream fixes):
https://kernel.ubuntu.com/~arighi/LP-1796292/4.15.0-54.58+lp1796292/
And, just in case, I've also applied the same set of fixes also to the latest bionic's master-next:
https://kernel.ubuntu.com/~arighi/LP-1796292/4.15.0-55.60+lp1796292/
Testing these two kernels should give us more information about the nature of the problem.
Thanks tons for the tests Ryan! Well, at least the hung task timeout trace is different, so we're making some progress.
With the new kernel it seems that we're stuck in bch_bucket_alloc(). I've identified other upstream fixes that could help to prevent this problem.
If you're willing to do few more tests, here's a new test kernel (based on 4.15.0-54-generic + set of bcache upstream fixes):
https:/ /kernel. ubuntu. com/~arighi/ LP-1796292/ 4.15.0- 54.58+lp1796292 /
And, just in case, I've also applied the same set of fixes also to the latest bionic's master-next:
https:/ /kernel. ubuntu. com/~arighi/ LP-1796292/ 4.15.0- 55.60+lp1796292 /
Testing these two kernels should give us more information about the nature of the problem.